The word itself is a morph between the instagator of the attack, BaccaYarro, and the word ambush. It describes an event during the First Trade war where BaccaYarro (as Captain Bellamy) and DoctorEckner (as Captain Eckner) ambushed Silver Empire Advanced Escort Carrier "Portus", a cargo ship, and its pilot, the (At the time) Director Spedius. The surprise attack initiated the war and crippled the Silver Empire's economy, resulting in a total loss of roughly 7.5 million Senarii worth of Quartz. (Later, however, $750,000 of the cargo was retrieved)
The attack was carried out with two SHSF monopods, which successfully bombed the flight deck of the carrier, thus incapacitating it from moving further, before destroying the cargo and fighters aboard. The wreck of this ship lingered at the site until cleanup crews salvaged what was left of the ship a few days after the attack.
The events of the Baccabush eventually caused Captain Bellamy to leave the known world from his actions in search of peoples to the east of the known world, ushering in his son, Captain Yarro, as his replacement.
It has become a general term to describe an ambush carried out against an airship, of generally which occurs in the same Renora-Aerie Straight of the original incident.